It works if you use {{ }} to encapsulate the string:
cabbageCreate("hrange", {{ bounds(466, 130, 500, 50), channel("min_duration", "max_duration"), range(0.25, 5, 0.25:1.5, 1, 0.001), text("Soundbyte Length (0.25s - 5s)"), trackerColour(99, 126, 171), textColour(175, 195, 255), colour(27, 55, 102) colour:0(27, 55, 102) }})
cabbageCreate("vslider", {{ bounds(996, 230, 150, 445), channel("volume"), range(0, 1, 0.75, 1, 0.01), text("Volume"), trackerColour(99, 126, 171), colour(27, 55, 102), textColour(175, 195, 255) }})
cabbageCreate("hslider", {{ bounds(466, 450, 500, 50), channel("reverb"), range(0, 1, 0.5, 1, 0.01), text("Reverb"), trackerColour(99, 126, 171), outlineColour(0, 0, 0, 50), colour(27, 55, 102), textColour(175, 195, 255) }})
It appears that the channels are somehow not registered in your code. I don’t know why, but until I figure it out, at least you have a work around.